commit 88ffff5ddbb8692ecb2c661aa29000dbde9eff8c
author Shane Harvey <shane.harvey@mongodb.com> Sat Aug 05 08:03:01 2017 -0700
committer Serhiy Storchaka <storchaka@gmail.com> Sat Aug 05 18:03:01 2017 +0300
tree 50134823f2cf3dfaf7a2cabbe143229d8fd4bd74
parent 5fbb8e367d4406f3248a60bed057f3b82d30f9ab

[2.7] bpo-31107: Fix copyreg mangled slot names calculation. (GH-2989). (#3004)

(cherry picked from commit c4c9866064f03646c686d7e08b00aeb203c35c19)

Lib/copy_reg.py

diff --git a/Lib/copy_reg.py b/Lib/copy_reg.py
index db17150..8943077 100644
--- a/Lib/copy_reg.py
+++ b/Lib/copy_reg.py
@@ -127,7 +127,11 @@
                         continue
                     # mangled names
                     elif name.startswith('__') and not name.endswith('__'):
-                        names.append('_%s%s' % (c.__name__, name))
+                        stripped = c.__name__.lstrip('_')
+                        if stripped:
+                            names.append('_%s%s' % (stripped, name))
+                        else:
+                            names.append(name)
                     else:
                         names.append(name)